Optimal acknowledgement strategies for multichannel reservation multi-access schemes under Rayleigh fading

A reservation-based medium access control (MAC) scheme is considered where users reserve data channels through a slotted-ALOHA procedure. The base station grants access to users in a Rayleigh fading environment using detectors that utilize measurements at the physical layer and system information at the MAC layer. The performance analysis is based on a Markov chain formulation and optimal performance obtainable in the given scenario is evaluated. An acknowledgement strategy based on cost-optimized Bayesian detectors which achieves this optimal performance is presented along with strategies based on other detectors such as MAP, ML and UMP. The delay/channel-utilization trade-off is considered for various system parameters.